Preheat the oven to 350 degrees Fahrenheit and grease a 9×13 baking pan.

In a saucepan, add butter, cocoa powder and water. Stir constantly until mixture begins to boil. Remove from heat and set aside.

In a mixing bowl, mix together flour, sugar, baking soda and salt. Add chocolate mixture and beat well.

Add eggs, buttermilk and vanilla and beat well.

Pour into the prepared pan and bake for 30-35 minutes or until a toothpick inserted into the center comes out clean. Let cool completely before topping with the frosting.

Beat the butter on medium speed with a hand held mixer or stand up mixer until the butter is smooth and creamy (2-3 minutes).

Add in the confectioner’s sugar, cocoa powder, 3 tablespoons of the heavy cream, vanilla extract and salt.  Mix on low speed until fully combined (approximately 1 minute).  Check the frosting consistency and add more heavy cream if needed.

Spread the frosting on the cooled cake.

Then the cake is ready to slice, serve and enjoy!